1. Field of the Invention
The present invention relates to a vacuum processing apparatus equipped with a particle counter and a cleaning device using the same, and more particularly, to a portable cleaning device for a vacuum processing apparatus such as a dry etching apparatus or a chemical vapor deposition (CVD) apparatus for fabricating semiconductor devices and a cleaning method therefor. Moreover, the present invention relates to a cleanliness diagnosis method using the above-mentioned portable cleaning device and also relates to a semiconductor fabricating apparatus capable of removing particles within a chamber of a processing apparatus for etching a semiconductor substrate surface of such as a semiconductor substrate or for forming films on the semiconductor substrate surface.
2. Description of the Prior Art
In a dry etching apparatus for etching a semiconductor substrate or a CVD apparatus for forming thin films on a semiconductor substrate, particles of reaction products accumulate within a vacuum chamber of the dry etching apparatus or the CVD apparatus when they are operated for a long period of time. Such particles staying in the vacuum chamber are blown up by a sharp increase of pressure when the vacuum chamber is opened to atmospheric pressure after the etching process or the film forming process is completed. Therefore, a problem that particles blown up may be adhered to the processed semiconductor substrate, resulting in a processing error.
As a countermeasure therefor, it has been usual in order to restrict the increase of inner pressure of the vacuum chamber to introduce air into the vacuum chamber gradually to thereby prevent accumulated particles from being blown up. However, this method is not reliable, since it is necessary to periodically pull out a wafer stage from the vacuum chamber and manually remove particles in the vacuum chamber. It is troublesome to clean a sequestered, large inner area of the vacuum chamber through a narrow carry in/out port thereof, resulting in a problem that it takes a long time to clean the vacuum chamber.
A vacuum processing method and apparatus for solving this problem is disclosed in JP H7-86241A. In a chamber cleaning means in the vacuum processor disclosed therein, a cleaning gas inlet and an exhaust gas duct are provided in a chamber, which is a vacuum processing chamber, and a movable electric dust catcher is provided within the chamber. In this vacuum processor, dry gas at atmospheric pressure is introduced into the chamber through the cleaning gas inlet to blow up foreign materials or aliens in the chamber so that the aliens are carried out externally of the chamber by the gas flow through the exhaust gas duct. Further, residual aliens are caught by the electric dust catcher arranged within the chamber.
Moreover, according to the disclosed technique, plasma is generated in the chamber to separate reaction products accumulated on an inner wall of the chamber from the latter during the cleaning operation using dry gas and floating reaction products is removed by performing the introduction and exhaustion of dry gas.
The above-mentioned prior art is disadvantageous in that the chamber cleaning means has to be provided every vacuum processor to be cleaned, so that the cost of the vacuum processor becomes high. Further, the chamber cleaning means has no means for confirming whether or not there is any residual particle, which are blown up and are to be removed, in the chamber. There is a possibility of existence of residual particles in the chamber unless such confirming means is used. That is, when inner pressure of the chamber is increased to atmospheric pressure after the required processing is performed, there is a possibility that the residual particles are blown up and contaminate the processed semiconductor substrate.
It has been known that the reaction products accumulated on the inner wall of the chamber are not naturally peeled off from the inner wall unless a long period of time lapses. This means that the separation of reaction products adhered to the inner wall of the chamber by means of cleaning plasma to be performed simultaneously with the removal of particles staying in the chamber for a relatively short time is useless step.
Furthermore, if the chamber is made of transparent quartz, it is easy to confirm the degree of accumulation of the reaction products on the inner wall thereof. However, when the chamber is made of a translucent material such as aluminum, it is difficult to confirm the accumulation degree of reaction products.
Moreover, the separation of reaction products adhered to the inner wall of the chamber by irradiating them with plasma is possible if the thickness of reaction products on the inner wall is less than a certain value. However, in order to completely separate reaction products from the inner wall, it takes long time and, therefore, the disclosed method for separating reaction products adhered onto the inner wall of the chamber from the inner wall is not always advantageous.
An object of the present invention is to provide a portable cleaning device, which can be generally used in various semiconductor processors to preliminarily clean an inside of a chamber of the semiconductor processor to such extent that particles in the chamber are not blown up at a time when the chamber is opened to atmospheric pressure, and a cleaning method using the same cleaning device.
The cleaning device according to the present invention includes a dry gas-jetting nozzle provided in a lid member for closing an opening of the chamber of the semiconductor processor. The nozzle is arranged such that dry gas is jetted along an outer periphery of a wafer stage within the chamber. Further, a gas discharge duct, a particle counter for monitoring the number of particles in the chamber, a pressure gauge for measuring pressure within the chamber and a pressure regulation valve for regulating pressure within the chamber are provided in the lid member.
The cleaning device preferably includes a plate member suspended from the lid member to partitioning the nozzle from an outlet of the gas discharge duct. Further, the cleaning device is preferably provided with a damper for regulating the amount of exhaust gas flowing through the discharge duct. Preferably, the cleaning device includes an angle regulating mechanism for changing an angle of the nozzle. Further, dry gas is preferably nitrogen gas and the lid member is preferably made of a transparent resin material.
A cleaning method according to the present invention is to be performing by the above-mentioned cleaning device. The cleaning method comprises the steps of reducing inner pressure of the chamber after the latter is shielded by closing the opening of the chamber by the lid member, blowing up particles residing in the chamber by jetting dry gas into the chamber and discharging the particles by discharging dry gas through the gas discharge duct while counting the number of the particles by the particle counter.
The present invention is not limited to the above-stated cleaning device and cleaning method but they can be widely applied to cleanliness diagnosis or other fabricating apparatus such as semiconductor fabricating apparatus using a vacuum chamber.
For example, a processing device having a particle counter is also belongs to the present invention, in which a vacuum has an opening portion. And a dry-gas jetting nozzle is provided in the chamber for jetting dry gas into the chamber. Further, a discharge duct is provided in the chamber for discharging the dry gas in the chamber. Needless to say, a particle counter is also provided in the chamber for monitoring the number of particles within the chamber.
In such a processing device having a particle counter, a wafer stage may be housed in the chamber. A lid member for closing the opening portion of the chamber can be used in such a manner that the nozzle and the discharge duct are provided in the lid member.
For the processing device mentioned above, a pressure gauge can be provided in the lid member for measuring inner pressure of the chamber. Further, a pressure regulator valve can be provided in the lid member for regulating inner pressure of the chamber and the nozzle is arranged such that the dry gas flows along an outer periphery of the wafer stage within the chamber.
This processing device can be used as a cleaning device, wherein the lid member has a structure capable of attaching a plurality of the chamber such that the chamber is cleaned by using the dry gas.
This processing device can be also used as a cleanliness diagnosis method, wherein the lid member is attached to the opening portion after cleaning an inside of the chamber, and the dry gas is jetted into the chamber while reducing inner pressure of the chamber through the discharge duct and counting the particles by the particle counter.
The above-mentioned processing device can be used as a cleaning device by further comprising a supporting stand within the chamber for fixing a part to be diagnosed of its cleanliness. In such a cleaning device the nozzle may be arranged so as to be movable while jetting the dry gas in a scanning mode.
When the processing device mentioned above is used as a semiconductor fabricating apparatus, the chamber may be provided with a nozzle for jetting a material gas for forming a film on a semiconductor substrate, and an exhaust duct is provided into the chamber for exhausting a reactive gas for the film.
In such a semiconductor fabricating apparatus, it may further comprises a movable member, and wherein the chamber is provided with a lid member to close the opening, and the lid member is provided with the nozzle, the discharge duct and the particle counter, whereby the movable member moves at a time of at least one of process for transporting the semiconductor substrate and forming the film in accordance with a program installed therein.